Transmitter apparatus



Feb. 15, 1927.]

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Filed Feb. 25, 1915 6 Sheets-Sheet 2 Witneoom Feb; 15 1927.

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- F. LOWENSTEIN TRANSMITTER APPARATUS Filed Feb. 1915 6 Sheets-Sheet 6LA 72 6 MM4b %?y 8 Wm 14211 Patented Feb. l5, 1927.

users sriefras rare] attests "r entice.

FRITZ LGWENSTEIN, OF ROCKAYVAY l' APvK lflElff YORK; JOEE"? G. WrlIT,ADMHISTRA- TOB- QF SAID FRITZ LOWENS'IEIN, DECEAfiED, ASSIGNGE, BYMESBTE ASSIGNMENTS,

T RADIO CORPGRATION OF AMERICA, A CGE'EGEATIQN OF DELAWARE.

TRANSMITTER APPARATUS.

Application filed February 25, 1915. Serial No. 10,592.

This invention relates to transmitter apparatus for use in wirelesssystems'of all kinds and especially in radio signaling installations.The principal objects of the invention' are to provide transmitterapparatus lengths; to enable change of wave length and also variation ofthe coupling to be offected from one point of control on thetransmitter; and to enable the coupling to be alteredpwithout therebyChanging the sellinductance of the secondary or antenna circuit. Theseand other objects of the invention are more fully set forth in thefollowing description and claims.

In most wireless telegraph systems now in practical use, the apparatusat the sending station comprises an antenna included in what is known asthe open or radiating circuit, to which circuit energy is supplied by aclosed or oscillating circuit, said oscillating circuit in turn beingsupplied with energy from any suitable source. circuit comprises a sparkgap, a condenser, a variometer, and an inductance, which inductanceusually constitutes the primary of the so-called oscillationtransformer. Tnductively coupled to the primary of the oscillationtransformer and forming a part of the open or radiating circuit is aninductance known the secondary of the oscillation transformer. Accordingto the best practice, the inductance of the open circuit, instead ofbeing concentrated in the'trans for ner secondary, is distributedbetween said secondary on the one hand and socalled loading coils ontheother, said loading coils being in circuit with the trans formersecondary but being so located that there is substantially no n'iutualinduction between the primary and loading coils. The present inventionis directed principally to those parts ofthe transmitter system comprising the primary and secondary of the oscillation transformer and theloading coils.

The oscillating The apparatus hereinafter described makes posslble theattainment of the above-enumerated objects in a simple and ready manner; andv inparticular, it enables the wave length in the closed andopen circuitsto be simultaneously changed with great rapidity andaccuracy without disturbing the tune of the set. 1

In order to make clear the principles of the invention, I haveillustrated in the accompanying drawings certain assemblages ofapparatus which-embody said principles and which have proved successfulin practice. It is not intended, however, to limit the invention to theparticular forms of apparatus herein disclosed, since said apparatus iscapable of various modifications and changes within the scope. of theinvention. In thesedrawings V Fig. 1 is a view in side elevation oftrans' mitter apparatus embodying the principles of the presentinvention;

Fig. 2 is a plan, and Fig. 3is a front elevation, of the same;

Figs. 4 and 5 are details, partly in sec tion; I I

Fig. 6 is a sectional view of the oscillation transformer and auxiliaryparts, on a larger scale;

Figs. 7 8 and 9 are details;

Fig. 10 is a fragmentary detail of another form of coil mounting;

1 "Fig. 11 illustrates diagrammatically the circuit connections involvedin the appara we of the foregoing figures; I

Fig. 12 illustrates another form of apparatus within the invention, andv Fig. 13 illustrates diagrammatically the circuit connectionscorresponding toFig- 12'.

Considering first that form of the apparatus illustrated in Figs. 1 to11, inclusive,,the oscillation transformer consists of spirally woundfiat or pancake coils and 21 constituting the primary andsecondary,respectively, of the 1 transformer. The primary coil ismounted on an elongated insulator hub 22, which, in turn, is mounted oninsulator plate 23. The secondary 21 of the. oscillation transformer issimilarly mounted on an insulator hub 24: secured to insulator plate25.The insulator hubs 22 and 24 may conveniently be made. of wood. Forconvenience, the insulator plates 23 and 25 will be hereinafter referredto as the front plate inductance of the secondary cir and therear plate,respectively,ot the transmitter. The loading coils 2.6 may also be ofthe pancake type as here shown,,and may be mounted on a common insulatorshaft 27. As many of these loading coils maybe provided as' isnecessary; in this instance, five such coils are shown connected inseries. The loading coils are shown as mounted with their axessubstantially at right angles to the axis of the secondary coil of theoscillation transformer, mutual self-inductance between said loadingcoils and secondary coil being thereby practically eliminated. (See Fig.

It. will be noted that the primary coil '20 is. here shown (Fig. 6) ashaving its adjacent outer turns spaced farther apart than the innerturns. This is to guard against breakdown due to excessively highditi'erences in potential which may exist between the outer turns of theprimary in actual operation. This greater potential difference intheouter turns is due first, to the greater self-inductance per turn onaccount of the greater diameter of the outer turns; and second, to thefact that when only one or two turns are in use (short wave lengthoperation). the-potential dili'erence per-turn is greater. Thus in thetypical instance shown in the drawings, the space 20 between the twooutermost turns may be about an inch, and the next succeeding .space 2Oabout three-quarters of an inch; while the remaining spaces 20 may beeach about half an inch. f

For the purpose of varying the coupling, the primary and secondary ofthe oscillation transformer are so mounted as to be relatively movable.To this end, either or both of the coils may be movably mounted. In thepresent example, the coils are axially alined and the primary isstationary, the front plate of thetransmitter carrying said primarybeing rigidly supported at 28 on the transmitter base 29 (Fig. 1). Onthe other hand, the rear transmitter plate carrying the secondary issupported on rollers resting on tracks 31, whereby the secondary may bemoved toward or awayfrom the primary in the direction of the commonaxis-s Since it is desirable that the secondary and the loading coilsshall always remain in the same position with respect to each other inorder to avoid ch 5a; in the cuit when the'coupling is altered,means areprovided to ensure the attainment of this result. As here shown, theshaft 27 carrying the loading coils is mounted on a carriage 82 which issupported on rollers 33 moving on track 34; and said carriage and therear plate of the transmitter are mechanically connected for movement inunison as by rigid members 35. By means of this arrangement thetransformer secondary and the loading coils may bemoved together as aunit.

The primary or" the oscillation transtorin er may be tapped at anyconvenient number 0;? points as by movable clips 86 (Figl 6), andconnected by leads 3'? to studs or terminals 88 mounted on the frontplate "of the transmitter.v By shifting the movable clips along thespiral conductor the positions of the tapping points are evidentlyadjustable. In the present example, the prm'iary 1s tapped oil at ninepoints which. are connectplate. For the sake of convenience inmal ingthe connections, two sets of nine studs each are provided on the primarytransmitplate here illustrated, the two sets being ed, respectively, tonine studs. on the front arranged on the circumference of acircle.

These two sets provide nine independent pairs or studs, each pa1r havingone of its members in one set and the other member in the other set. Forthe sake of clearnessthe studs in each set have been numbered from 1 to9; and it will be seen that thepairs con- 39 spans the front transmitterplate and is rotatably mounted thereon in such manner as to sweepduplicate brushes 40 over the two sets at studs and thus to connect thepairs of studs successively, thus making the two members of each pair ineffect the same point electrically. lVhile this duplicate arrangement ofstuds is v ry convenient, it is not essential, and any other suitablearrangement may be employed. The said bar 39 may be suitably connectedby conductor a'l and lead el-l to the closed circuit 01 the oscillationsystem; while either end of the primary coil 20 (in this instance theouter end) is connected as by lead42 (Fig.1) to said. closed circuit.

The secondary of the oscillation trans former is tapped in a similarmanner and at the same number of points as the primary. Movable clips 43and leads 43a connect the ta )ping-otl' points to a set of inde pendentstuds id on the rear plate of the transmitter, this set-being here shownas lo cated on thelower portion of said plate and comprising nine studs.Another set of nine studs 45 on the upper portion of" therreartransmitter plate is also provided; and these upper studs or tern'iinalsare electrically connected, respectively, by suitable means, here shownas comprising metal strips 46, leads 4:6 and movable clips 47, toadjustable tap ping points on the loading coils. For the sake ofconvenience, said loading coils are wound alternately clockwise andcounterclockwise, beginningat the centers ot: the

' t-rically isolated.

bar orswitch 52, 5?, from one ofsuch coils; so that the connection 48between the firstand second coils is near outer peripher 'ies,whereasconnection ll) between the second and third coils is made nearthe centers oi said coils, anc. so on 'lor theother connections 50, 51.This method of winding the loading coils obviously simplif e In order toconnect any one of the studs n of the lower set inseries with thecorresponding studs or the upper set, an elec trically conductive bar isrotatably mounted on the rear transmitter plate. On account of thehigher potential difference existing in operation between adjacent studs45 as compared to that between adjacent studs 44:, studs e5 areadvantageously spaced farther apart than studs ist. As here shown, bothsets are arranged on circular arcs, that on which studs 45 are locatedhaving the greater radius. This arrangement also renders more convenientthe'described connec* tion of studs to the loading coils. The arms 53 ofthe conductive connecting bar are therefore of unequal length in theconstruction here shown, each arm carrying a brush 5% arranged to makecontact successively with the studs of the two sets so as to connectradially opposite studs in pair successively. It is to be understoodthat connectorbai: 52, 58 is electrically connected only to that pair ofstuds which it connects in any given position and is otherwise elec- Inthe arrangement described, the circuit relation between the secondary ofthe oscillation transformer and the loading inductance is evidently suchthat for any operative position or" the connector hi r 52 53 a certainproportion of the secondary ot the. oscillation transformer is connectedin series with a certain proportion of studs 44L on the rear transmitterplate repre' sent substantially the same inductance value of the coil.Fence shitting the connector cent studs 41-4: to the next does not varno secondary coil inductance materially, while it does vary the loadinginductance. fine end of the secondary pancake coil, in'this instance theouter end, may beconnected in the antenna circuit as by lead 55 (Fig.2); while one terminal of the series of loading coils may also beconnected as by lead 56 to said antennacircuit. The tapping'points, inthis example nine in number, oi the primary 20, the secondary 21, andthe loading coils 26, may be so adjusted by means of the n'iovablecontact clips,that when the connector bar and the connector bar 52, 53are in corresponding positions, the wave length or, in other words, theoscillationperiods of the closed and the antenna circuits, are the same.

-Means are provided whereby the wave lengthsoi' the primary andsecondary circuits, that is the. closedand antenna circuits, may besimultaneously changed, and to this end the rotatable connector bars orswitches carried by the front and rear plates of the transmitter aremechanically connected so that, they may be moved simultaneously. Themeans here. shown for accomplishing this comprise an operating'shalt 57of wood or other non-conductive material which extends through thetubular hubs 22 and 23, and to which the connector bar on the rear plateof the transmitter is securedias by pin 58. For a purpose to beexplained later, the actuating connection of shaft ,57 to the li'rontconnector bar 39 is effected ,by means of leather key 59 or someequivalentmeans. A controlling handle 60 is suitably secured to bar 39for the purpose of swinging the same over th studs on the front plate.As here shown, the said handle is secured in a SOCliGtlIlQlYlbEl 61rigid with hub 62 of the bar 39. When the controlling handle is swungaboutthe axis of the transmitter to vmove connector bar 39, shaft 57 isrotated accidental displacement of the parts, the

connector bar or switch lever 39 carries a stop 39 which is pressed by.spring 39 against the particular stud 38 to whichthe lever is turned.

In order to vary the coupling; between the primary and secondary,.meansare prov1ded for varying; the coupling d1sta-nce between coils 20 and21. As here shown, this is accomplished by moving the secondary coilaxially away from or toward the primary coil, this movementbeingpermitted by the feather-key connection above described betweenconnector bar 39 and operating shaft ill) .sar' for var in the cou alin23 b 'chani'cally in various ways,but the arrange- .gitudinal axis, itis evident that pinion 64 will operate upon rack 63 to move shaft 57forwardly or rearwardly as may be neceS-. Owing to the mechanicalconnection between the secondary and the loading coils, the latter willof course be moved simultaneously to exact :ly the same extent as thetransmitter secondary; and hence the self-inductance of the secondarycircuit, considered by itself, remains constant since there is no changein the mutual inductance between the secondary and the loading coils. Itisalso to be noted that the movement of the described elements as a unitprevents any twisting, short-circuiting, or variation of the inductanceof the leads connecting the same.

It willbe seen that the described operation of the controlling handle invarying the coupling may be carried out either alone or in conjunctionwith the operation of said handle in changing wavelengths; and that theoperator may effect either or both move- .ments of said handle with onehand, while his other hand is left entirely free. Apparatus ofthischaracter I believe to be broadly new in the practical wireless art.

hen a' certain optimum coupling distance has been found, it is desirableto be able to lock the apparatus in this position so that accidentalmovement'of the moving parts by reason of outside disturbing influencesmay be prevented. This may be accomplished, for example, by mounting alocking pin 66 in socket member 61 in posi tion to enter the spacesbetween the teeth of the pinion 64 when the handle 60, which islongitudinally slidable in the socket, is moved into the position shownin Fig. 5, where the pinion is locked. It is also convenient to providereadily adjustable means for holding the, controlling handle either inor out of locking position. Such means may comprise a detent member 67mounted in the socket 61 and yieldingly pressed by spring 67 against thesurface of the controlling handleor rod in such manner as to entereither of the circumferential grooves or recesses 67" or 67 in thehandle according as the controlling handle is in orout of lockingposition. The handle is readily shifted fromone position to the otherwhen desirechagainstthe yielding restraint of the detent; but accidentalshifting is effectually prevented. Under the usual operating conditions,it

is ordinarily desirable to maintain a con stant coupling distance at thedifferent wave lengths so that only one operation is needed for a changeof wave length. If, for example, with the set in tune at a particularwave length, the coupling distance necessary for best operation is foundto be shorter than that desired to be maintained as the constantcoupling distance, the number of turns in the secondary of theoscillation transformer should be increased, and the number of turns inthe loading coils de creased, sutiiciently to maintain resonance,

these changes being made to the extent necessary to increase thecoupling distance to that desired. Located at a convenient point belowthe front transmitter plate as at 68,

is the double throw series parallel condense-r switch which may be usedto decrease the valueof the capacity under ordinary conditions in theclosed or primarycircuit so-as to make it possible to operate-at lowerwave lengths. When operating from the right of the front plate of thetransmitter, it is most convenient to have switch 68 located at the leftand to have the controlling handle or lever of the'quiclechange switchmechanism extending to the right, as shown in Fig. 3. As few radiooperating rooms are alike as regards size, arrangement of ground, antenthe transmitter. For this purpose thetransinitter base is provided withopenings 69 below the right-hand corner of the front transmittcr plate,whereby the .switch 68 and the leads to the condenser may be readilytransferred to the other side of the apparatus. in changing theqriicl-clia1ige switch from the position shown in Fig. 3 to the position foroperation at the left of the transmitter, the operator proceeds asfollows: The pin 58 holding the rear lever or bar 52, 53 to theoperating shaft is removed, and-the stops 38 are turned through an angleof 90 to permit rotation of the front lever or bar 39 through an angleof 180. Holding the rear lever 52, 58 stationary, the controlling handleorlever is swung through an arc of 180, the operating shaft 5? beingthereby turned the same distance. Rear lever 52, 53 is now again securedto the shaft by replacing pin 58, and the stops 38 are a ain turned backto their initial positions to iimit the motion of the bar 39. The flator pancake coils mentioned above are of spiral con- .struction and haveparticular advantages for the purposes sought. Said coilsconsist of aflat ribbon conductor 70 spirally wound and carried by a framecomprising insulator .53 on the rear transmitter plate.

tubes which are mounted radially onan insulator hub such as 22, 24 inFig. 6. These tubes have parallel transverse grooves or slots 71 thereininto which the edge of the conductor ribbon is in erted as th coil iswound. To prevent the conductor from being pulled out of'these grooves,the conductor is tongued at suitable intervals before winding, asindicated at 7 2. lVhen the ribbon is inserted into the groove thetongue is pressed flush with the surface of the conductor; but after thetip of the tongue has passed the inner surface of the tube, the

pressure is released and the tongue springs outwardly, thus locking theconductor in place on the insulator tube. The ends of the tube may beclosed by plugs 73 of wood or the like.

Another method of mounting the fiat conductor ribbon is illustrated inFig. 10. Ac-

cording to this construction, round headed screws 7 1 are fastened tothe insulator tubes; and into the slots of these screws the of the bandor ribbon conductor is soldered. The screws are located in such manneras to give a spiral coil, ordinarily of uniform pitch.

Although of special utility in the appa ratus here shown, the pancakecoils above described are of general application wherever coils of thisform can be usefully employed for inductance, or for other purposes suchas resistance.

The relation of the circuits involved in the transmitter apparatus asabove described is shown diagrammatically in Fig. 11 where 75 and 76represent the primary and secondary, respectively, of a resonancetransformer supplying energy to the closed circuit comprising spark gap77, condenser 78,

series-parallel condenser switch 79, variometer 80, and the primary 20of the oscillation transformer. The antenna circuit ineludes thesecondary 21 of the oscillation transformer, loading coils 26, andantenna 81, the circuit being grounded as indicated at 82. Thequick-change switch is diagrammatically indicated at movable contact 85corresponding to switch lever 39 on the front plate of the transmitter,and movable contact 86 corresponding to switch lever 52,

As indicated, the tapping-01f points on the primary and secondary of theoscillation transformer and on the loading coils are individuallyvariable for purposes of adjustment; 81 is the lightning switch, whileswitch 81 serves to connect the antenna either to the transmitter or toa receiver at 81.

In Fig. 12 is illustrated another form which the quick-change switchmechanism may assume. This form has been successfully used in connectionwith atransmitter system of which the circuitrelations are illustratedin the diagram of Fig. 13. Re-

transmitter system at 110, said antenna circuit including variableinductance 111 and the secondary 112 of the oscillation transformer, andbeing connected to ground through the primary helix and coupling coil. Ahot wire animeter 113 may be inserted in the ground connection. I

As indicated in the drawing, the helices 10 1 and 112 are tapped 011' atappropriate points and connected to four groups of contact pointsdesignated (A B G D E), (a b a I d e), (21 13 G D E), and (a b c d e).'lhese taps are arranged in such manner that the primary and secondarytransmitter circuits remain in syntony for any position of the movableswitch devices 11 1 and 115. Operation of switch device 114 changes thewave length in both circuits simultaneously in large steps; whileshifting switch device 115 gives changes in small steps intermediate thewave lengths" represented by any two consecutive positions of switchdevice 11 1.

The coupling coil 105 is so mounted on a movable shaft or the likeindicated at 116' that its angular position relative to the primary ofthe oscillation transformer may be varied to change the couplin Themechanical devices diagrammatically illustrated in Fig. 13 forcontrolling wave lengths and coupling are conveniently embodied in thearrangement illustrated in Fi 2 in such manner that from one point ofcontrol on the transmitter the wave lengths in both the primary andsecondary circuits may be varied without disturbing syntony, and thecoupling may also be changed either alone or in conjunction withthechanges in wave length. In this showing, the contact points crresponding to the points at which the helices are tapped 011 arelettered to correspond with the same points shown'in Fig. 13. Contactbrush 117 of the primary helix and contact brush 118 of the secondaryhelix are one piece mechanically and are placed in opposite directionson one arm operable by means of lever 119. By swinging said leverthrough the arc of a circle, the contact brushes are thereby movedsimultaneously and the wave lengths in both circuits are changedsimultaneously in relatively large steps. Handle 119 is provided with abeveled gear 120 which meshes with beveled gear 121 on a disk 122 whichis operatively connected withcoupling coil 105 (Fig. 13) in such mannerthat when the disk is revolved, the coupling is varied. Handle 119 maybe turned about its longitudinal axis to revolve said disk through theagency of the beveled gears before described, and hence is operable notonly to vary the wave lengths in quick succession over a comparativelylarge range, but is also operable to alter the coupling. If the handleor lever is permanently connected to bevel gear 120, when said handle isswung through an arc to move contact brushes 117, 118, the engagement ofbevel gears 120,121, will compel coupling disk 122 to turn at the sametime, provided said handle is held against turning movement about itsown longitudinal axis. If the handle be permitted to turn about its ownaxis during the swingingmovement, however, the bevel gear 120 simplyturns idly in mesh with bevel gear 121, without moving thecoupling disk.

The fine adjustment of the Wave lengths may be accomplished by turningthe wheel 123 to move contact brushes 12 1 and 125 through the agency ofbeveled gears 126, 127, and insulated connecting shaft 128.

It is evident that wheel 123 maybe left in any one position and lever119 operated to give five different wave lengths; or lever 119 may beleft in one position and the wheel turned to move brushes 124 and 125over their contact points, whereby another set of five wave lengths maybe obtained in quick succession, these latter wave lengths, however,being intermediate two consecutive wavelengths obtainable by operationof lever 119; In this .way without disturbing the tune of the set, thewhole operating rangeof wave lengths may be swept with great rapiditybyrthe operator, while at the same time adjustment to any particularwave length may be quickly and accurately secured. The transmitter maytherefore be adjusted readily to any wave length desired without thenecessity of several distinct operations and without recourse to charts.or diagrams for purposes of calculation. The arrangement also evidentlyaffords effective means forinterference when desired.

An intermittent gear 129, 130 may be also provided whereby, after eachcomplete revolution of wheel 123, the lever 119 is au tomaticallyadvanced to the next contact point. In this way twenty-live differentwave lengths may be obtained by turning @wheel 123 continuously throughfive complete revolutions. A suitable wave length scale may be providedas at 131. Part of the subject matter described and claimed herein isdisclosed in my prior application, S61. No. 569,324, filed June 28,1910.

What I claim is:

1. Wireless transmitter apparatus comprising an oscillatory circuitcontaining the primary of an oscillation transformer," an

antenna circuit containing the secondary of said transformer, sets ofcontacts electrl contact members simultaneously to vary the wave lengthwhile maintaining substantial syntony.

2. Wireless transmitter apparatus comprising an oscillatory circuitcontaining the primary of an oscillation transformer, an

antenna circuit containing the secondary of said transformer, sets ofcontacts respectively connected to tapping-oft points on said primaryand secondary, contact mem bers connected in said circuits and movableto engage contacts in said sets, and common means operable to move apair of said con tact members simultaneously to vary, the wave lengthwhile maintaining substantial syntony.

3. l/Vireless transmitter apparatus comprising an antenna circuit, anoscillating circuit associated therewith, variable tuning means in eachcircuit, sets of contacts electrically connected to said tuning meansand representing, respectively, different electrical values thereof,contact members respectively movable over said sets of contacts andincluded in said circuits, and common means operable to move saidcontact members simultaneously to vary the electrical period of saidcircuits according to a regular relation. 7 v

4. lVii-eless transmitter apparatus comprising an antenna circuit, anoscillating circuit associated therewith, variable tuning inductance ineach circuit, sets of contacts electrically connected to said tuninginductances and representing, respectively, different electrical valuesthereof, switch members each movable over a set of said contacts forsyntonizing said circuits, and common means whereby said switch membersmay be moved to vary the electrical period of the circuitssimultaneously.

5. A circuitarrangement comprising operatively associated oscillatorycircuits in cluding variable tuning means, a variable coupling betweensaid circuits, and a controlling member operable to vary either saidtuning means or said coupling.

6. A circuit arrangei'nent comprising operatively associated oscillatorycircuits in' cluding variable tuning means, a variable coupling betweensaid circuits, and a controlling member operable to vary eithersaidtuning means or said coupling, or to vary both together.

7. Wireless apparatus comprising two oscillatory circuits, anoscillation transformer having its primary in one circuit and itssecondary in the other, sets of cont-acts con nected, respectively, totappingcli points on the primary and secondary of said transformer,switch members movable toengage contacts in said sets and thereby toplace in circuit'different inductance values of said primary andsecondary, and an operating handle mechanically. connecting a pair ofsaid switch members and operable to move them simultaneously intoengagement with the corresponding contacts to vary the wave length whilemaintaining substantial syntony.

8. lVireless transmitter apparatus comprising an oscillationtransformer, loading,

inductance in circuit with the secondary thereof, members movable tovary the selfinductance of the primary and secondary, respectively, thecircuit relation between said secondary and said loading inductancebeing such that the latter varies when the secondary is varied, andmeans mechanically connecting said members and operable to move the samesimultaneously.

.9. l Vireless transmitter apparatus comprising the combination, with anoscillation transformer,and means for maintaining the primary andsecondary thereof a fined distance apart, of loading inductance incircuit with said secondary, and means for varying the self-inductance.of said primary, and of said secondary, the circuit relation betweensaid secondary and said loading inductance being such that variations inthe former occasion variations in the latter.

10. Wireless transmitter apparatus comprising an oscillation transformerof which the secondary is so mounted as to be movable with respect tothe primary, and loading incombination, with an oscillation transformercomprising inductively associated flat primary and secondary coils inaxial alim'nent, and a loading coil in circuit with said secondary coiland arranged with its axis sub stantially at right angles to the axisofsaid secondary coil, and means mechanically con necting said secondarycoil with said leading coil for simultaneous movement with respect tosaid primary coil.

13. In wireless transmitter apparatus comprising an oscillationtransformer of which the primary and secondary are so mounted as to berelatively movable to vary the coupling, in combination with loadinginductance in circuit with said secondary and in fixed position relativeto said. secondary, whereby the coupling may be varied without alteringthe selfinductanceof the secondary circuit. I

14. Wireless apparatus comprising the combination with an oscillationtransformer, and mechanism for adjusting the coupling distance betweenthe primary and secondary coils thereof, of means for locking saidmechanism for any adjusted position of said coils. 1

15. l/Vireless transmitter apparatus comprising the combination with anoscillation transformer, of loading inductance in circuit with thesecondary thereof, the inductance of said secondary and the loadinginductance being adjustable with respect to each other for operation ata constant optimum transformer couplin distance, and common meansoperable to vary simultaneously the primary inductance and the combinedsecondary and loading inductance for difi'erent wave lengths.

ldl i ireless transmitter apparatus comprising the combination with anoscillation transformer, and loading coils in circuit with thetransformer secondary, of common switch means operable to varysimultaneous ly the effective inductance of the transformer primary, thetransformer secondary. and the loading coils, respectively.

17. Wireless transmitter apparatus which comprises, in combination, apair of flat spiral coils constituting the primary and secondary of anoscillation transformer, switch levers operable to vary the oifectivcinductance of said coils, and mechanism operable either to vary thecoupling distance between the coils, or to move said switch levers tovarythe effective inductance ofboth coils simultaneously.

18. Wireless transmitter apparatus which comprises, in combination, apair of flat spiral coils constituting the primary and secondary of anoscillation transformer, switch levers operable to vary the eflectiveinductance of said coils, and mechanism operable to vary the couplingdistance between the coils and at the same time to move said switchlevers to vary the effective inductance of both coils simultaneously.

19. Wireless transmitter apparatus comprising, incombination, anoscillationtransformer having flat spiral primary and secondary coilseach supported on a frame carried by a central hub, separate sctsofcontact points associated with said coils, each set electricallyconnected with selected points onthe corresponding coil, a switch leverfor each set, and means extending through said hubs and operable to movesaid switch levers simultaneously.

20. ll ireless transmitter apparatus com' prising the combination withan oscillation transformer, and loading coils for the secondary circuit,of a set of contacts electrical- 1y connected to tapping points-on thetransformer prlmary, a switch device operable to move over saidcontacts, a second set of contacts electrically connected to points onthe transformer secondary, a third set of contacts elecrically connectedto points on said mary, loading coils associated with the sec-- onclarycoil and mounted for movement therewith, switch means movable to bringvariable proportions of the secondary coil and of the loading coils intocircuit, switch means movable to bring variable proportions of theprimary coil into circuit, a shaft connecting said switch means forsimultaneous opera tion thereof, said shaft being slidable through thestationary hub and secured against axial movement relatively to themovable hub but revoluble relatively there to, and a controlling handleoperable either to rotate said shaft for simultaneous operation of saidswitch means, or to move said shaft longitudinally to vary the coupling.distance between said primary and secondary coils.

22. Wireless apparatus comprising a pair of coils arranged to constitutean oscillation transformer, in combination with separate sets ofcontacts, one set for each coil, leads connecting each set of contactsto tapping points on the corresponding coil, and interconnected switchmeans cooperating with said contacts.

23. Wireless apparatus comprising a pair of flat spiral coils mounted inparallel spaced relation and constituting an oscillation transformer, incombination with plates, one for each coil, located convenientlyadjacent said coils, a set ofcontacts carried by each plate, leadsconnecting each set of contacts with adjustable tapping points on thecorresponding coil, and interconnected switch means cooperating with thecontacts carried by each plate.

24. Wireless apparatus comprising a pair offiat spiral transformer coilsmounted in parallel spaced relation and capable of relative movement inan axial direction, a pair of plates disposed on the non-adjacent sideof said coils, each plate being fixed in position. relative to itscorresponding coil, a Set of contacts on each plate, leads connectingeach set of contacts with tapping points on the corresponding coil, and.interconnected switches cooperating with the sets of contacts.

25. l l ireless appaatus comprising a pair of relatively movable coilsassociated to constitute an oscillation transformer, two sets ofcontacts each set con ected totapping points on one of said coils andfixed in position relative to such coil, and interconnected switch meanscooperating with said contacts 2'7. l Vireiess apparatus comprising apri mary transformer coil, switch means associated therewith andcooperating'wlth tapping points on said COll, a secondary transformercoil, switch means associated therewith and cooperating with tappingpoints thereon, each coil being fixed in position relative to itsassociated switch means, but movable together with its associated switchmeans relatively to the other coil, and means to vary the transformercoupling, and a common controlling member located on one side of one ofthe coils for operating both said switch means.

28. Wireless apparatus comprising aprimary transformer coil, switchmeans associated therewith and cooperating with tapping points on saidcoil, a secondary transformer coil, switch means associated therewithand cooperating with tapping points thereon, each coil being fixedinposition relative to its'associated switch means but movable togetherwith its associated switch means relatively to the other coil, and meansto vary the transformer coupling, and a common controlling memberlocated on one side of one of the coils for operating both said switchmeans and also for varying thecoupling.

29. il ireless apparatus comprising the combination, with flat spiralcoils in parallel spaced relation and relatively movable in an axialdirection, and switch means for each coil operable to vary the eifectiveinductance thereof, of a rotatable element mechanically connecting saidswitch means and movable longitudinally, a rack carried by said element,a pinion capable of meshing therewith, and a controlling handle operableto rotate said element and thereby to move said switch means, and alsooperable to turn said pinion and thereby to move said elementlongitudinally and vary the coupling distance between the coils.

30. Wireless apparatus comprising the combination, with an oscillationcircuit, and an antenna circuit associated therewith, of common meansoperable to vary the Wave length in both circuits simultaneously inrelatively large steps, and common means for varying the wave lengths inboth circuits simultaneously in smaller steps intermediate the largersteps. 7

31. In a system of wireless signaling, the combination, with an antennacircuit, of two inductance devices included in the an- 'tenna circuit, aseries of contact devices for conductor and arranged to be adjustableover a corresponding section of its respective inductance device, andmovable means common to both series of contacts for making a conductiveconnection from any desired contact device of one series to anoperatively related contact device of the other series.

32. Wireless apparatus comprising an antenna system containing capacityand inductance, an oscillatory system containing capacity andinductance, a coupling for said systems and common means for simultaneously connecting said capacity, inductance and coupling to vary theoscillation period while maintaining each system substantially insyntony.

In testimony whereof I hereunto aflix my signature.

FRITZ LOWENSTEIN.

